Hi all, new to the board today.

I have about 800 sq ft of 3/4" IPE decking, i.e., not tongue and groove, that I would like to use as a flooring in my basement. I would be going over concrete slab. These planks are 8 feet long and have parallel grooves on the underside.

My questions:

1) what sort of concrete prep do I need? sealed concrete? vapor barrier? plywood subfloor?

2) what sort of fastener: nails? stainless screws? glued directly to floor (see per question 1)?

3) how much of a gap would I need between the sides and ends of each board?

4) what do you recommend for stainin/sealing the wood?

I have read a bunch online but most do not directly address IPE at least that I can find.

I appreciate all of your help on this project.

I would be checking the moisture first. Decking is not usually dried the same way or to the extent that you find in flooring. Next installing that wood down on concrete & below grade (im assuming due to it being a basement) is going to be a challenge. Not trying to be a smart a.... but I would consider selling the decking and buying some flooring that is made to be glued down to the slab.
Now if I were to do it, I would put in a floating subfloor down over 6mill plastic lapped up the walls that consisted of two layers of 1/2" ply stapled together. your still going to have take the planks somewhere to put a t&g on the boards(make sure its where you want it m/c wise prior) then nail down to the subfloor as usual.

Yea, I would have to agree with Kevin's first thought.....sell the ipe and use the money to buy an engineered product.....installing that below grade is just asking for trouble, IMO.

Thank you both for your input. The decking has been around for quite a while, i.e., bought it at auction and has been acclimating to my basement for ~6 months. I have not tested my floor moisture yet and will do so. The basement is at a constant temp all year !67 degrees if that makes a difference.

Assuming there is little to no moisture now, could I expect more in the summer months with the consistent temp?

I do have a router table etc that I could rout in the T and G, although I imagine that it will mess up some bits.

For fastening, I am not concerned with concealing the screws etc but rather would like the more "rough" look to having the screws on top of each board.

If you're wanting to install decking in your basement, then I would install it like decking instead of flooring.

Cover all the concrete slab with 6-8 mil polyethylene and lap up the walls. Then attach 2 x 4 PT sleepers 12" OC. These should be no more than 48" long and off set with each other. They would be laid perpendicular to the direction you want the decking to go. Make sure they are not wet. Much PT is wet and needs to be allowed to dry. Various methods exist but Tapcon screws or anchors would seem to be the most secure. I would personally seal the backside of all the deck boards prior to installing with a quality clear sealer to help in moisture absorption. Then lay the deck board. There are various methods you could employ. One is deck clips that are hidden. This would look nice. Another is galvanized finish nails and urethane adhesive. Another is stainless steel screws. If screwing, I'd use the smaller head screws with square or hex drive. All the boards butt ends land over a sleeper and are supported by the sleepers. You'd leave small gaps between the boards, 1/16" should be sufficient as long as there are no big RH swings and the wood's be acclimated. After install, use the finish of choice. I'd recommend a oil-type or Waterlox. A urethane can have problems with IPE. Plus oils allow easy touch ups.

Milling T&G's into the boards is a waste of time and not needed if you install the boards as I described.

Are all of the troubles with this just do to using IPE or is plank flooring just difficult? Or is it because it is decking material and not actual flooring material? I have seen a video where IPE with T and G was glued directly to concrete but not the decking material.

The issue is you're dealing with a solid board as opposed to a more stable engineered product. No matter how "dry" the home is, below grade basements will have higher than ideal humidity levels which cause problems with solid floors, and you can't know for certain that the moisture conditions in the basement today are what they will be tomorrow, next week, next year. It's a crapshoot at best to attempt installing it at all in a basement.

Then we get into glueing.....many adhesives say they are suitable for gluing solid flooring, and some manufacturers allow it, but I think you will find that the majority of us are opposed to gluing solid materials other than pattern floors and parquet. For one, you need to have a vapor barrier between the slab and the wood, so even if you glue, you need to first use a vapor barrier compatible with the adhesive. The bigger concern is boards that have slight warp (bow or ski) and how you expect to hold those tight to the slab...plus you are dealing with very long boards (8')....even in shorter lengths you can expect to have some slight bow or ski to a board, but 8' lengths and a strong wood like Ipe, there's no way you could expect all of those to sit flush to the floor on their own and I doubt an adhesive would be strong enough to hold them tight if you manage to force them flush to the slab.

Nailing is the only way to go in my opinion, but then again you're still working underground!

Okay, I understand. How about a combo of the above: slats with glue and screws? Can the slats be 3/4 - 1" x 2-3" rather than 2"x4"?

I think I like the idea of putting down a 6 mil poly, screwing 3/4 inch plywood strips about say 3 inches wide, on 12 inch centres, and gluing and screwing the IPE to these.
On word of caution: the dust generated by cutting and sanding of IPE is toxic. Wear proper respirators when working with this wood, properly balloon off the work space to prevent spread of dust to other areas, and do a surgical clean-up when done.

I am thinking the same thing and appreciate all of the comments to my post. I got the IPE SUPER cheap at auction and if this doesn't work for some reason and I have to remove it, I will not be that concerned.

Thanks for the tip on the dust - I will work outside with a proper respirator

I would HIGHLY recommend using pressure treated wood or treating the wood yourself. In my area, using wood on or below grade that's not PT would not meet code. The plastic does reduce vapor emissions to negligible but due to insect infestation, PT is required.

Okay, will do. Thanks

By treating the wood myself (sleepers) do you mean something like Thompsons water seal?

NO! Use this.

http://www.acehardwareoutlet.com/%28zlh ... GoogleBase